Coscinoderma nardorus ( Lendenfeld, 1886 ) Lendenfeld, 1886

Sutcliffe, Patricia R., Hooper, John N. A. & Pitcher, Roland, 2010, The most common sponges on the Great Barrier Reef seabed, Australia, include species new to science (Phylum Porifera), Zootaxa 2616, pp. 1-30 : 12-15

Coscinoderma nardorus ( Lendenfeld, 1886) comb. nov.

( Figures 6 , 7 )

Aphrodite nardorus Lendenfeld, 1886 [1885]: 306.

Hippospongia nardorus ; Hooper & Wiedenmayer, 1994 (2005 web version): 384. Hippospongia aphroditella Lendenfeld, 1889: 36 [in key, see also Lendenfeld, 1889: 312, pl. 11 figs 11–14, pl. 12 fig.

13); unjustified replacement name for Aphrodite nardorus Lendenfeld, 1885 ]. Ceratodendron haeckeli Marshall, 1892: 5 .

Material examined. Holotype. BMNH 1886.8.27.105 wet (=AM G3398 slide, figured in Lendenfeld, 1889, pl. 12 fig. 13, Palm Is., Torres Strait, QLD, 10°25'S 142°10'E. Paratype. BMNH 1930.8.13.181 dry.

New material. QMG329979 (SBD500371), seabed on outer shelf south of Myrmidon Reef, Great Barrier Reef, 18° 31΄ 29ʺ S 147° 35΄ 0 6ʺ E, 74 m depth, epibenthic sled, 22 ix. 2003, coll. RV Lady Basten. QMG329120 (SBD507175), seabed on inner shelf of Swains Reef, adjacent to Herald’s Prong No. 2, Great Barrier Reef, 21° 47΄ 0 6ʺ S 151° 21΄ 54ʺ E, 85 m depth, trawl, 7 xii. 2003, coll. FRV Gwendoline May. QMG330307 (SBD524660), seabed east of Palm Island, Great Barrier Reef, 18° 42΄ 17ʺ S 146° 48΄ 18ʺ E, 35 m depth, epibenthic sled, 30 iv. 2004, coll. RV Lady Basten .. QMG330304 (SBD523195), seabed west of Ribbon Reef No. 4, Great Barrier Reef, 15° 25΄ 30ʺ S 145° 41΄ 0 6ʺ E, 48 m depth, trawl, 17 x. 2004, coll. FRV Gwendoline May.

Other material: 129 specimens collected between the seabed adjacent to MacLennan Reef # 2 in the far northern GBR and Swain Reefs in the south ( Figure 6 ). Housed at the Queensland Museum, Brisbane, Australia.

Description. Shape. Stalked, with long basal root or holdfast. Stalk and root can comprise more than half of the total length of the sponge. The main body of the sponge is globular.

Colour. Light pink colour in situ and on deck. Specimens turn beige when preserved in ethanol and stain the ethanol a bright yellow colour. When removed from the water, the sponge emits a fluorescent pink dye.

Oscules. Terminal to the globular body of the sponge, oscules can be numerous, with up to ten oscules visible in the larger specimens. Each oscule is surrounded by a raised lip to a height of 1–15 mm, depending on the size of the specimen.

Texture and surface characteristics. Compressible sponge which is very dense and retains a substantial amount of water within the main body. The surface is almost entirely covered by microconules, raised up to 0.5 mm from the surface, but can be smooth in some areas. Stalk and root are smooth. Internally cavernous, the surface is irregularly pitted with deep channels and large inhalant pores.

Skeletal structure. The ectosome is armoured with sand grains. Irregular primary fibres cored with sand can protrude through the ectosome, or become more apparent further within the choanosomal structure. The choanosome is dominated by a dense, confused mass of clear secondary fibres. Small sand grains are lightly scattered throughout the choanosome.

Habitat and distribution. Found in reef areas and sandy bottoms, this sponge is attached to rubble in soft sediment by a holdfast. It is distributed in Torres Strait and throughout the entire length of the Great Barrier Reef seabed ( Figure 6 ) at depths between 12 and 85 m, predominantly in benthic substrates dominated by sand and calcium carbonate material.

Remarks. This species is very characteristic and immediately recognisable by its external stalked clubshaped growth form as Lendenfeld’s species Aphrodite nardorus . Lendenfeld (1889) subsequently transferred it to Hippospongia , where it has remained until the present, albeit with virtually no subsequent citation over the past century (see Hooper & Wiedenmayer, 1994 (2005 web version)).

The generic definition of Hippospongia was revised in 2001 ( Cook & Bergquist, 2001), to clarify misidentifications between Spongia and Hippospongia . Species were reclassified, new species of Spongia were described, and only three species were left assigned to Hippospongia ( H. communis ( Lamarck, 1814) , H. gossypina ( Duchassaing & Michelotti, 1864) and H. lachne (de Laubenfels, 1936)). The question of the best assignment for the remaining species still classified in Hippospongia was left open.

Cook and Bergquist (2001) revised the choanosomal skeleton of Hippospongia as containing rare, irregular and sometimes cored primary fibres occurring predominantly near the surface, with secondary fibres dominating. The subdermal lacunose structure is a characteristic feature and the oscular canals are large, retaining approximately the same width throughout the body of the sponge as the oscules themselves. The unarmoured ectosomal layer is also an important primary characteristic in the key to the genera of Spongiidae ( Cook & Bergquist, 2002) . Consequently, ‘ nardorus ’ does not conform to this revised definition and is more appropriately allocated to Coscinoderma based upon the presence of an armoured ectosome, irregular, cored primary fibres and a thin, unorganised, dense reticulation of secondary fibres. This is in contrast to the only other genus of Spongiidae with an armoured ectosomal layer, Rhopaloeides , which contains very thick secondary fibres in the choanosome ( Cook & Bergquist, 2002).

The inclusion of the nominal species C. haeckeli into synonymy with this species was based on superficial comparison of the respective (mostly dried) type material ( Hooper & Wiedenmayer, 1994), not through a modern analysis using fresh material. Hence this reported synonymy should be regarded as a tentative hypothesis given their disparate geographic distributions (Bass Strait versus Torres Strait and the GBR).

Predicted distributions and biophysical preferences. Coscinoderma nardorus was found consistently along the length of the GBR at depths ranging from 12 to 85 m, with the highest populations found in the Townsville/Cairns regions ( Figure 6 ). Specimens were collected from 85 sled sites (biomass 21.4 kg) and 42 trawl sites (biomass 22.4 kg), living in benthic habitats dominated by sand and carbonate ( Figure 3 ) distributed across the shelf. Analysis of environmental correlates showed preference for low variation in salinity and a negative correlation to high mud substrates ( Figure 6 ). The stalked, root-like base of the sponge allows settlement on mobile substrates.

Figures

FIGURE 3. Substrate composition plot, showing the relative composition of sand, carbonate, gravel and mud for four species (Dercitus xanthus sp. nov., Xenospongia patelliformis Gray, 1858, Coscinoderma nardorus (Lendenfeld, 1886) and Spheciospongia vagabunda (Ridley, 1884 )).

FIGURE 6. Model distribution map displaying predicted and actual distribution and biomass of Coscinoderma nardorus (Lendenfeld 1886) from the Great Barrier Reef seabed, displaying: OTU code for this species (SCQMSB. BRS 192537), P-AUC: Area Under the Curve performance diagnostic for the Presence / Absence model; Dev. Ratio: Deviance Ratio (P- AUC) performance diagnostic for the Biomass model; Measuresled: a device factor accounting for the difference in sampling rates between devices; Measuretrawllog (AreaHa) and Measuresledlog (AreaHa): offsets accounting for the swept area sampled by the trawl and sled; and influential predictor variables including: CRS _ S _ SD: influential predictor variables of standard deviation of salinity (psu), Along: along shelf gradient, GA _ MUD / GA _ MUD ^ 2: mud grainsize fraction (%) and its quadratic term.

FIGURE 7. Coscinoderma nardorus (Lendenfeld, 1886) (QMG 329979 (SBD 500371 )). A, Top view of the ectosomal skeleton (scale bar 2 mm). B, Cross section of the skeleton, showing cored primary tracts protruding through the ectosome (scale bar 1 mm). C, Fibre network within the choanosome (scale bar 500 μm). D, QMG 330307 (SBD 524660). Specimen (scale bar 9 cm).